In my final year at Northwestern, a group of Mechanical Engineering seniors and I consulted for a Northrop Grumman manufacturing team to automate a washer-placement process previously completed by hand. In this process, washers just 5mm in diameter were placed in shallow counterbored holes so that an automated robot arm could fit a screw inside the washer, pick up the washer with a vacuum, and fasten the screw-washer assembly onto another device. This process was done at irregular time intervals. The client desired that the only inputs be a bag of washers dumped in the device and the press of a button to turn it on.
Our thought process separated this task into two smaller systems: the first would organize bulk washers into a neat queue, and the second would select one at a time from the queue for placement. The final product delivered to the client consisted of a rotating drum with grooves to pick up washers, bring them to a tube at the center of the drum, and stack them in a vertical queue. Infrared LEDs and corresponding sensors placed around the clear vertical tube instructed the drum to turn when washers in the queue were low. A disc with the same shallow counterbores as in the original process would then slide beneath the tube, selecting one washer and bringing it to the pickup point. An inductance sensor below the pickup point identified the presence of a washer and instructed the disc to bring another after the robot arm had taken the one at the pickup point. A microcontroller managed sensor output, actuation of motors, and errors communicated to the operator and the surrounding automated manufacturing cell.
My primary roles on the team were to manage the packaging and assembly of the product in CAD (we primarily used SolidWorks), design and prototype various components in the machine shop and 3D printing lab throughout the project, and create CNC programs to machine precise parts for the final product. The group held weekly meetings for design reviews, project management, and feedback from our professors and our clients at Northrop.